London: Leicester moved back to the top of the Championship with a 1-0 win over Reading, while previous leaders Burnley slumped to a 1-0 defeat at Middlesbrough on Thursday.
David Nugent fired home his eighth penalty of the season to give Nigel Pearson`s team the points at the King Power Stadium.
Nugent scored from the spot in the 21st minute after Anthony Knockaert had been brought down by Shaun Cummings to claim his 12th goal of the season.
A series of power failures in the first half threatened the game but it was completed with the use of an emergency generator as Leicester kept on course in the promotion race.
At the Riverside Stadium, Burnley crashed to a disappointing loss as Emmanuel Ledesma sealed the points for the struggling hosts.
Ledesma, who also scored at Millwall in his previous appearance, got the 24th minute winner as Middlesbrough recorded back-to-back wins for the first time in 2013.
Fourth placed Derby were left to rue Chris Martin`s missed penalty as Huddersfield snatched a 1-1 draw.
Craig Bryson handed Steve McClaren`s Derby a 30th minute lead, three minutes after Martin failed to convert that spot kick.
But with four minutes remaining Martin Paterson fired into the roof of the net to steal a share of the spoils for Huddersfield, denying Derby the opportunity to go level on points with Burnley.
David McGoldrick`s brace took his season`s tally to 11 and helped Ipswich claim a 3-0 win at Doncaster, with Luke Chambers netting the third.
Lawrie Wilson`s brace and a goal for Yann Kermorgant sealed struggling Charlton`s 3-2 home victory over Brighton.
Jose Ulloa scored twice for Brighton but his second didn`t come until second half stoppage-time.
Blackburn failed to find a way to break down stubborn Sheffield Wednesday in a dour 0-0 draw at Ewood Park.
New Watford manager Guiseppe Sannino secured his side`s first league victory in 11 matches as they thrashed 10-man Millwall 4-0 at Vicarage Road.
Troy Deeney converted a penalty after Danny Shittu was sent off for the foul that brought the spot kick.
Fernando Forestieri, Ikechi Anya and Lewis McGugan added the other goals in Watford`s first win since the departure of boss Gianfranco Zola.
On-loan Manchester United forward Jesse Lingard was sent off for Birmingham, but his side held on for a 0-0 draw at Wigan.
Matt Richie scored twice as Bournemouth condemned lowly Yeovil to comprehensive 3-0 defeat on the south coast, the other goal coming from Eunan O`Kane.
Neil Danns` second-half goal claimed a 1-0 victory for Bolton at Barnsley.
In the first of the day`s late matches, play-off hopefuls Leeds drew 1-1 at Blackpool.
Then third-placed QPR missed the chance to go level on points with leaders Leicester after crashing to a 2-0 defeat at Nottingham Forest.
A first half header from Greg Halford and a late strike from Andy Reid lifted Forest back into the top six as Harry Redknapp`s side suffered a second consecutive defeat.
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